Per Wiberg is the keyboardist and mellotron player for the Swedish progressive death metal band Opeth, and a member of Michael Amott's stoner rock band Spiritual Beggars. Wiberg had toured with Opeth since the 2003 Deliverance/Damnation tour, and officially joined Opeth in 2005. Wiberg provides backing vocals for Opeth in addition to his keyboard duties.

He played the keyboard in the intro to "Enemy Within" by the melodic death metal band Arch Enemy. He has also played piano on Swedish progressive rock band Anekdoten's 1993 release Vemod.